[17/31] x86: Optionally dump code bytes on cpu_dump_state

Submitted by Marcelo Tosatti on Jan. 24, 2011, 9:02 a.m.

Details

Message ID f5c848eed769b795ac9c06bfb315e4aa9116337c.1295859760.git.mtosatti@redhat.com
State New
Headers show

Commit Message

Marcelo Tosatti Jan. 24, 2011, 9:02 a.m.
From: Jan Kiszka <jan.kiszka@siemens.com>

Introduce the cpu_dump_state flag CPU_DUMP_CODE and implement it for
x86. This writes out the code bytes around the current instruction
pointer. Make use of this feature in KVM to help debugging fatal vm
exits.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
 cpu-all.h            |    2 ++
 kvm-all.c            |    4 ++--
 target-i386/helper.c |   21 +++++++++++++++++++++
 3 files changed, 25 insertions(+), 2 deletions(-)

Patch hide | download patch | download mbox

diff --git a/cpu-all.h b/cpu-all.h
index 4ce4e83..ffbd6a4 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -765,6 +765,8 @@  int page_check_range(target_ulong start, target_ulong len, int flags);
 CPUState *cpu_copy(CPUState *env);
 CPUState *qemu_get_cpu(int cpu);
 
+#define CPU_DUMP_CODE 0x00010000
+
 void cpu_dump_state(CPUState *env, FILE *f, fprintf_function cpu_fprintf,
                     int flags);
 void cpu_dump_statistics(CPUState *env, FILE *f, fprintf_function cpu_fprintf,
diff --git a/kvm-all.c b/kvm-all.c
index 10e1194..41decde 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -832,7 +832,7 @@  static int kvm_handle_internal_error(CPUState *env, struct kvm_run *run)
     if (run->internal.suberror == KVM_INTERNAL_ERROR_EMULATION) {
         fprintf(stderr, "emulation failure\n");
         if (!kvm_arch_stop_on_emulation_error(env)) {
-            cpu_dump_state(env, stderr, fprintf, 0);
+            cpu_dump_state(env, stderr, fprintf, CPU_DUMP_CODE);
             return 0;
         }
     }
@@ -994,7 +994,7 @@  int kvm_cpu_exec(CPUState *env)
     } while (ret > 0);
 
     if (ret < 0) {
-        cpu_dump_state(env, stderr, fprintf, 0);
+        cpu_dump_state(env, stderr, fprintf, CPU_DUMP_CODE);
         vm_stop(0);
         env->exit_request = 1;
     }
diff --git a/target-i386/helper.c b/target-i386/helper.c
index 6dfa27d..1217452 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -249,6 +249,9 @@  done:
     cpu_fprintf(f, "\n");
 }
 
+#define DUMP_CODE_BYTES_TOTAL    50
+#define DUMP_CODE_BYTES_BACKWARD 20
+
 void cpu_dump_state(CPUState *env, FILE *f, fprintf_function cpu_fprintf,
                     int flags)
 {
@@ -434,6 +437,24 @@  void cpu_dump_state(CPUState *env, FILE *f, fprintf_function cpu_fprintf,
                 cpu_fprintf(f, " ");
         }
     }
+    if (flags & CPU_DUMP_CODE) {
+        target_ulong base = env->segs[R_CS].base + env->eip;
+        target_ulong offs = MIN(env->eip, DUMP_CODE_BYTES_BACKWARD);
+        uint8_t code;
+        char codestr[3];
+
+        cpu_fprintf(f, "Code=");
+        for (i = 0; i < DUMP_CODE_BYTES_TOTAL; i++) {
+            if (cpu_memory_rw_debug(env, base - offs + i, &code, 1, 0) == 0) {
+                snprintf(codestr, sizeof(codestr), "%02x", code);
+            } else {
+                snprintf(codestr, sizeof(codestr), "??");
+            }
+            cpu_fprintf(f, "%s%s%s%s", i > 0 ? " " : "",
+                        i == offs ? "<" : "", codestr, i == offs ? ">" : "");
+        }
+        cpu_fprintf(f, "\n");
+    }
 }
 
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